According to ESPN, the Cavs felt that tickets for friends and family members were a tad too pricey:

The Warriors offered the Cavaliers lower-level tickets, in the corners of the arena, to buy for their friends and family for $1,300 each. Last year, those tickets were about half that price, sources said.

A Warriors spokesperson said prices went up for fans and players on both teams because of supply and demand. […] Golden State officials could not confirm that Warriors players were charged the same price as Cavaliers players were, but they did say that the location of the seats was the same as the team was offered last year for the Finals.

The $1,300 price still comes at a discount as compared to the face value of those seats for season-ticket holders, who pay $1,600 each.